StateMachineTutorial.java

/*
 *      Copyright (C) 2012, 2016  higherfrequencytrading.com
 *      Copyright (C) 2016 Roman Leventov
 *
 *      This program is free software: you can redistribute it and/or modify
 *      it under the terms of the GNU Lesser General Public License as published by
 *      the Free Software Foundation, either version 3 of the License.
 *
 *      This program is distributed in the hope that it will be useful,
 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *      GNU Lesser General Public License for more details.
 *
 *      You should have received a copy of the GNU Lesser General Public License
 *      along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.openhft.chronicle.map.ipc;

import net.openhft.chronicle.map.ChronicleMap;
import net.openhft.chronicle.map.ChronicleMapBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;

/**
 *
 */
public class StateMachineTutorial {
    private static final Logger LOGGER = LoggerFactory.getLogger(StateMachineTutorial.class);

    // *************************************************************************
    //
    // *************************************************************************

    public static void main(String[] args) {
        ChronicleMap<Integer, StateMachineData> map = null;

        try {
            File dataFile = new File(System.getProperty("java.io.tmpdir"), "hft-state-machine");
            map = ChronicleMapBuilder.of(Integer.class, StateMachineData.class)
                    .entries(8).create();

            if (args.length > 0) {
                if ("0".equalsIgnoreCase(args[0])) {
                    StateMachineData smd =
                            map.acquireUsing(0, new StateMachineData());

                    StateMachineState st = smd.getState();
                    if (st == StateMachineState.STATE_0) {
                        long start = System.nanoTime();

                        //fire the first state change
                        smd.setStateData(0);
                        smd.setState(StateMachineState.STATE_0, StateMachineState.STATE_1);

                        while (!smd.done()) {
                            // busy wait
                        }

                        long end = System.nanoTime();

                        LOGGER.info("Took {} us for 100 transiction", (end - start) / 1E3);
                    }
                } else if ("1".equalsIgnoreCase(args[0])) {
                    StateMachineProcessor.runProcessor(
                            map.acquireUsing(0, new StateMachineData()),
                            StateMachineState.STATE_1,
                            StateMachineState.STATE_1_WORKING,
                            StateMachineState.STATE_2);
                } else if ("2".equalsIgnoreCase(args[0])) {
                    StateMachineProcessor.runProcessor(
                            map.acquireUsing(0, new StateMachineData()),
                            StateMachineState.STATE_2,
                            StateMachineState.STATE_2_WORKING,
                            StateMachineState.STATE_3);
                } else if ("3".equalsIgnoreCase(args[0])) {
                    StateMachineProcessor.runProcessor(
                            map.acquireUsing(0, new StateMachineData()),
                            StateMachineState.STATE_3,
                            StateMachineState.STATE_3_WORKING,
                            StateMachineState.STATE_1);
                } else if ("clean".equalsIgnoreCase(args[0])) {
                    LOGGER.info("deleting {}", dataFile.getAbsolutePath());
                    dataFile.delete();
                }
            }
        } finally {
            if (map != null) {
                map.close();
            }
        }
    }
}